Effect of axial shoulder external rotation exercise in side-lying using visual feedback on shoulder external rotators.

[Purpose] This study aimed to determine effectiveness of axial side-lying wiper exercise using the visual feedback with a laser pointer on infraspinatus and posterior deltoid muscles. [Subjects and Methods] The subjects were 22 healthy adults (18 males, 4 females) in their 20s who consented to participate in the present study. Surface Electromyography was used to measure the infraspinatus and posterior deltoid muscle activity before and after an intervention. The intervention consisted of performing side-lying wiper exercise with a 1-kg dumbbell and a ruled paper for 30 minutes. [Results] The infraspinatus illustrated significantly increased muscle activity after intervention. The posterior deltoid also showed increased activity after intervention but it was not significant. [Conclusion] Axial side-lying wiper exercise using the visual feedback has the therapeutic effectiveness for the selective infraspinatus muscle strengthening. Therefore it can be useful to provide shoulder movements with stability.